For example, an electronic control unit disclosed in JP 2014-154745 A (patent literature 1) is an electronic device including a semiconductor module, a wiring substrate and a case member, and radiating heat generated in the semiconductor module through the case member.
The electronic control unit disclosed in the patent literature 1 includes a semiconductor module, a substrate, a frame end and a first heat conducting member. The substrate and the frame end correspond to the wiring substrate and the case member.
The semiconductor module includes a body with a rectangular parallelepiped shape, and terminal portions projecting from a side surface of the body. The semiconductor module further includes a first metallic board exposing from a surface of the body portion opposing to the substrate. The first metallic board corresponds to the terminal portion. The substrate has a first wiring pattern to which the first metallic board is electrically connected, and second wiring patterns to which the terminal portions are connected. The frame end is made of metal. The frame end includes a body portion opposing to the substrate, to which the semiconductor module is electrically connected. The frame end further includes a first specific shape portion projecting from the body portion toward the substrate and forming a small first clearance with the first wiring pattern. In order to form the small first clearance, the first specific shape portion projects to a position nearer the first wiring pattern than a surface of the body of the semiconductor module opposing to the frame end. The first heat conducting member has an electrical insulation property and is disposed in the first clearance.
Heat generated in the semiconductor module is conducted to the first specific shape portion through the first metallic board, the first wiring pattern and the first heat conducting member. Then, the heat is radiated outside through the body portion of the frame end.